MIDI 2 integrations

libremidi integrates with the existing MIDI 2 ecosystem.

cmidi2

We ship Atsushi Eno's cmidi2 header-only MIDI 2 implementation as part of the library. This allows to quickly match incoming messages with MIDI 2 types. A lot of useful utility functions are provided.

See the midi2_echo.cpp example: it uses the following printing function:

std::ostream& operator<<(std::ostream& s, const libremidi::ump& message)
{
  // Automatic conversion from libremidi::ump& to cmidi2_ump*
  const cmidi2_ump* b = message;
  
  // Read MIDI 2 information
  int bytes = cmidi2_ump_get_num_bytes(message.data[0]);
  int group = cmidi2_ump_get_group(b);
  int status = cmidi2_ump_get_status_code(b);
  int channel = cmidi2_ump_get_channel(b);
  s << "[ " << bytes << " | " << group;

  switch ((libremidi::message_type)status)
  {
    case libremidi::message_type::NOTE_ON:
      s << " | note on: " << channel << (int)cmidi2_ump_get_midi2_note_note(b) << " | "
        << cmidi2_ump_get_midi2_note_velocity(b);
      break;
    case libremidi::message_type::NOTE_OFF:
      s << " | note off: " << channel << (int)cmidi2_ump_get_midi2_note_note(b) << " | "
        << cmidi2_ump_get_midi2_note_velocity(b);
      break;
    case libremidi::message_type::CONTROL_CHANGE:
      s << " | cc: " << channel << (int)cmidi2_ump_get_midi2_cc_index(b) << " | "
        << cmidi2_ump_get_midi2_cc_data(b);
      break;

    default:
      break;
  }
  s << " ]";
  return s;
}

ni-midi2

It is possible to enable compatibility with [ni-midi2](https://github.com/midi2-dev/ni-midi2, the MIDI Association-backed MIDI 2 implementation. This is done with the LIBREMIDI_NI_MIDI2 CMake switch: -DLIBREMIDI_NI_MIDI2=ON.

An example of initialisation of a MIDI 2-compliant communication can be found in the midi2_interop.cpp example.

Note that due to the complexity of MIDI 2, we believe end-users will want to build their own, custom-tailored stack and API on top of these base layers.

Current interoperability features are:

• libremidi::ump can be converted to midi::universal_packet and conversely.
• libremidi::midi_out::send_ump can be called with midi::universal_packet, midi::sysex7_packet and midi::sysex8_packet.

This ensures that most MIDI-CI messages can be sent directly. Example:

libremidi::midi_out midiout;

...

midiout.send_ump(midi::ci::make_discovery_inquiry(my_muid, id, 0x02, 512));